I got the answer but I cant figure out how to write?

Question

The diameter of a certain atomic nucleus is 6.50x 10-5 pm and its mass is 9.40 x 10-25 g. What is the density of the nucleus in grams per centimeter cubed ? Assume the nucleus is a sphere with a volume equal to 4/3 P r 3

Enter a numeric answer only, no units. Use at least the correct number of significant figures.



To enter a number in exponential notation use an e for the exponent
eg 2.34 x 106 enter as 2.34e6 2.34 x 10-16 enter as 2.34e-16

Density = Mass / Volume

Mass = 9.40 x 10-25 g

Volume = 4/3*3.1415* (6.5x10-5cm / 2)^3 = 1.438x10-13

Density =6.537x10-12 gm/cc
how to write this without using 10.

I tried 6.537e-12
i tried 6.6e-12
but it didnt work!

Answer 1

Diameter is given as 6.50e-5 (three significant figures).
Mass is given as 9.40e-25 (three significant figures)

Volume = 4/3 * pi * (radius) * (radius) * (radius)

Doing the math to obtain density, we get a number like 6.537e-12 (this has 4 significant figures).

To be as accurate as the data we started with, we need the same number of significant figures (i.e. 3).

Rounding off the answer to 3 sig figs = 6.54e-12